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https://issues.apache.org/jira/browse/CASSANDRA-6385?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jonathan Ellis updated CASSANDRA-6385:
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Reproduced In: 2.0.2, 1.2.11, 1.2.9 (was: 1.2.9, 1.2.11, 2.0.2)
Since Version: (was: 1.2.9)
Priority: Minor (was: Major)
> FD phi estimator initial conditions
> -----------------------------------
>
> Key: CASSANDRA-6385
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6385
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Quentin Conner
> Assignee: Jonathan Ellis
> Priority: Minor
> Fix For: 1.2.13, 2.0.3
>
> Attachments: 6385-v2.txt, 6385-v3.txt, 6385.txt
>
>
> phi estimates are calculated for newly discovered nodes from an un-filled
> (new, uninitialized) deque.
> The inter-arrival time (elapsed time between gossip heartbeats) is stored in
> the o.a.c.gms.ArrivalWindow.arrivalIntervale deque for each received
> heartbeat, up to the maximum window size of 1000 samples.
> In the o.a.c.gms.FailureDetector.interpret() method, phi is calculated for
> the node which uses a statistical measure called variance. Like mean,
> variance on a population (a set of numbers or measurements) is not
> statistically relevant unless the population set size is 30 or greater.
> When a new node is discovered, the calculated variance is higher than normal,
> and causes phi to be higher than normal, resulting in a false positive
> failure detection.
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